1. Field of the Invention
The invention concerns a ceramic blade for a cutting tool, in particular a knife.
2. Description of the Invention
Until now the available blades of a cutting tool, in particular a knife, have been made almost exclusively of steel. They comprise a cutting edge, which transitions into two side surfaces, and an upper surface running opposite to the cutting edge. Further, securing means in the form of cover plates or link plates or the like are provided, via which it is possible to secure to the grip or handle. In the case of pocket knives a bore hole is provided, through which a mounting bolt anchored in the handle passes, so that the blade can be folded in.
The upper surface of the blade is formed as a planar surface and is relatively broad by design, so that by placement of the index finger or, as the case may be, by application of the palm of the hand, the user can exercise force from above and the cutting edge can be pressed into the material to be cut and/or drawn through it. The transition to the sides is designed to be sharp-angled.
Occasionally cutting tools in the form of knives have been available in commerce, of which the blades are made of a ceramic material. In comparison to the steel blades described in the introductory part above, these possess the advantage of a higher wear resistance, which translates into a substantially higher usable life. A re-sharpening or re-grinding is not necessary following conditions of normal use.
These ceramic blades do not differ from the conventional steel blades with respect to their geometric design, of which the shape has remained unchanged.
Although ceramic blades represent an excellent alternative to the hitherto employed steel blades, a series of disadvantages has come to light in daily conventional use, which until now have hindered their broad acceptance. So it has been found, that this type of blade is highly liable to breakage as soon as a certain bending strain is exceeded. In particular, with very hard ceramic materials, such as for example aluminum oxide, this results as a rule in the premature termination of the usable life, since bending forces can hardly be avoided in daily use. The end of the useful life is thus frequently reached early as a result of an unintentional bending force, although the cutting edge remains fully functional as necessary for the cutting function.